Risk Factors for Early Postoperative Morbidity and Mortality following Extremity Metastatic Pathologic or Impending Fracture Fixation

Background. As cancer survivorship continues to improve, the perioperative morbidity and mortality following surgical treatment of metastatic bone disease become an increasingly important consideration. The objective of this study is to identify risk factors for early postoperative complications and mortality following extremity prophylactic fixation and pathologic fracture stabilization. Methods. A single-centre retrospective review of 185 patients (226 total surgeries) who underwent prophylactic fixation or pathologic fracture stabilization for extremity metastatic bone disease between 2005 and 2020 was performed. Skull, spine, pelvic, and revision surgeries along with diagnosis of primary bone neoplasm were excluded. Univariate, multivariate, and subgroup analyses were performed to identify predictors and independent risk factors for 30-day postoperative morbidity and mortality. Results. Primary cancers included lung (n = 41), breast (n = 36), multiple myeloma (n = 35), prostate (n = 16), lymphoma (n = 11), renal cell carcinoma (n = 10), and other (n = 36). The 30-day postoperative complication and mortality rates were 32.30% (n = 73) and 17.26% (n = 39), respectively. The most common complications were pulmonary-related, cardiac events, surgical site infection, sepsis, and thromboembolism. Pathologic fracture, presence of extra-skeletal metastases, longer surgical duration, and blood transfusion requirements were associated with 30-day postoperative complications overall. A past medical history for cardiac disease was also associated with systemic but not local surgical complications. Pathologic fracture, presence of extra-skeletal metastases, lung cancer, blood transfusion requirements, and increasing pack-year smoking history were predictors for 30-day mortality. In the multivariate analysis, pathologic fracture (p=0.016) and presence of extra-skeletal metastases (p=0.029) were independent predictors of complications. For mortality, pathologic fracture (p=0.014), presence of extra-skeletal metastases (p=0.0085), and increased blood transfusion requirements (p=0.048) were independent risk factors. Conclusions. The findings of this study provide additional guidance for perioperative risk assessment and patient counselling. Additionally, improving clinical assessment tools to identify and quantify patients at risk of pathologic fractures becomes increasingly important given the significant morbidity and mortality associated with pathologic fracture treatment.